Twitter is great. It allows us (among other things) to keep up to date with the latest news, watch events unfold in real time and pass comment on them for the whole world to see. For brands it’s an invaluable resource, providing them with the means to easily converse with fans, generate buzz around their products and potentially reach whole new markets simply by word of mouth.

So far, so good. Until, of course, it all goes horribly, horribly wrong…

Recently there have been a few high profile examples of Twitter backfiring on brands – moments where the angry teeth of the internet are bared in all their grizzly glory, leaving social media teams wishing the earth would swallow them whole. But as these brands found out, when something goes wrong on Twitter there’s no getting away from it, it’s there for everyone to see.

The majority of Twitter-related brand jams are the result of a poorly conceived hashtag. In the mind of the brand it’s easy to see why starting a personalized hashtag might seem like a good idea; if it begins trending then that’s some of the best publicity the internet has to offer – all for next to no money. However, when looking through those rose-tinted spectacles it’s easy to overlook one very key factor: as a brand, you don’t get to dictate how the Twittersphere uses your hashtag.

Take the recent debacle surrounding Qantas Airways, for example. The Australian airline recently fell foul of its own #QantasLuxury hashtag in spectacular form, after it was hijacked by irate Twitter users looking to vent anger about its poor customer service and spate of grounded planes. The same later happened to McDonald’s, whose #McDStories tag was overrun with unsavoury anecdotes from unhappy customers and brand-baiting animal rights activists alike. Finally, in the wake of their spectacular collapse of service at the end of last year, Blackberry recently found itself on the receiving end of a torrent of abuse after it invited users to #bebold, and share their thoughts via Twitter.

The main problem in all three of these cases is that the brands allowed themselves to forget one of the golden rules of the internet: any skeletons in your closet can (and often will) come back to haunt you. In each instance it resulted in a profoundly embarrassing (and above all public) episode, and one that had to be openly acknowledged as a failure of marketing strategy.

Of course, that’s not to say brand hashtags always fail. Click here to see a rundown of some of the more successful ones nominated for an award at the SHORTY social media awards this year.

With this in mind, our advice to anyone considering the hashtag route of viral marketing would be to think long and hard before providing the internet with its own, unmoderated soapbox to voice opinion on your brand.

In the right circumstances it can work wonders, but get it wrong and you might just find yourself pushed off it…